Product Features:
The triple frequency power generator, triple frequency voltage generator, and triple frequency high voltage generator are designed to meet the requirements of <>, <> and >—1995 for triple frequency induced withstand voltage tests and partial discharge tests.
The induced withstand voltage test for transformers and instrument transformers is an important test to verify whether the product meets national standards. The longitudinal insulation induction test of interlayer, inter-turn, segment, and phase-to-phase insulation is an important item to verify whether the winding meets requirements. To increase the test voltage of the winding without saturating the transformer or instrument transformer core excessively, which would lead to excessive excitation current, the test frequency needs to be increased, generally to 100Hz—400Hz.
There are multiple methods to obtain a 100Hz—400Hz power supply, among which the more applicable ones include:
① Combination of three variable frequency generators (100Hz—400Hz);
② Combination of three single-phase transformers (150Hz), and the most convenient is the second method.
The combination method of three single-phase transformers: the primary side is star-connected, and the secondary side is open-delta connected. When the core is not saturated, the main magnetic flux it produces must be a flat-topped wave. Since the flat-topped main magnetic flux contains a significant third harmonic component Φ3, and the frequency of the third harmonic flux f3=3f1, the main flux induces a third harmonic phase electromotive force.
Since the primary side is star-connected and the secondary side is open-delta connected, the core operates in a saturated state, and the no-load current I appears as a peaked wave. In addition to the fundamental component, it also contains higher harmonics. Among the higher harmonics, the amplitude of I is relatively large. Due to the open secondary, the three-phase fundamental components cancel each other out, leaving only the third harmonic output.
The entire unit's voltage output is achieved by tuning to resonance at a 150Hz power supply. When the voltage rises, a certain squealing sound during resonance is normal.
Technical Parameters:
Rated capacity: 5-100kVA
Input: three-phase 380V, 50Hz sine wave
Output: 0-300V, 0-500V, 0-1000V (special voltages customized), 150Hz,
Waveform distortion ≤1%
Capacity: 3-150kVA
No-load operation time: ≤5 minutes
Load operation time: 40-60 seconds
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